[Checkins] [zopefoundation/DocumentTemplate] 3c53d1: Remove the `diff` flag from isort

[Jürgen Gmach]

  Branch: refs/heads/fix-flake8
  Home:   https://github.com/zopefoundation/DocumentTemplate
  Commit: 3c53d187ee8f80cbb50fbb8ad65f6f06aadeab30
      https://github.com/zopefoundation/DocumentTemplate/commit/3c53d187ee8f80cbb50fbb8ad65f6f06aadeab30
  Author: Jürgen Gmach <juergen.gmach at googlemail.com>
  Date:   2020-10-08 (Thu, 08 Oct 2020)

  Changed paths:
    M tox.ini

  Log Message:
  -----------
  Remove the `diff` flag from isort

... as it causes `isort` to return an return code of 0!
(This means the isort run is successful, even when there are wrongly
sorted imports).

The surprising behaviour of the `diff` flag is working as intended:
https://github.com/PyCQA/isort/issues/1039

modified:   tox.ini